Typically it takes a few weeks for Sirius to do the channel update. In addition, for the stiletto, to get new Icons, you either need to listen via Wifi or plug your radio into your computer and get the ZAP updated. The forum over at the Digital Radio Central has a lot of Stiletto subscribers who are always the first to know when there is a firmware update.

A lot of times, the Wifi channels are updated much sooner than the Bird channels, but that does not help you out in the car.